A lot from the age of 4-6, the happiest years so far. I remember a lot from the rest of my childhood as well, but those sucked so they don't count. The former are the ones i cherish and i don't want to live without.
Do you ever wish you were a child again?
edit: Q2: Do you ever get nostalgic and want to visit the place where you grew up (ie if you haven't seen it in a long time)?